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Intel
®
IXP400 Software
Programmer’s Guide IXP400 Software Version 2.0 April 2005
Document Number: 252539, Revision: 007 297
Access-Layer Components:
USB Access (ixUSB) API 22
This chapter describes the Intel
®
IXP400 Software v2.0’s “USB Access API” access-layer
component.
22.1 What’s New
There are no changes or enhancements to this component in software release 2.0.
22.2 Overview
The Intel
®
IXP4XX Product Line of Network Processors and IXC1100 Control Plane Processors’
USB hardware components comply with the 1.1 version of the Universal Serial Bus (USB)
standard.
22.3 USB Controller Background
The IXP4XX product line and IXC1100 control plane processors’ Universal Serial Bus Device
Controller (UDC) supports 16 endpoints and can operate half-duplex at a baud rate of 12 Mbps
(slave only, not a host or hub controller).
The serial information transmitted by the UDC contains layers of communication protocols, the
most basic of which are fields. UDC fields include:
Fields are used to produce packets. Depending on the function of a packet, a different combination
and number of fields are used. Packet types include:
Packets are then assembled into groups to produce frames. These frames or transactions fall into
four groups:
• Sync • Endpoint • Data
• Packet identifier • Frame number • CRC
• Address
• Token • Handshake
• Data • Special
• Bulk • Interrupt
• Control • Isochronous